I don’t know if Claudio still reads this but a short note if he does. After 3 years of using his gadjet I have worked my way down from 1.15 mm wedges to .35 wedges. Just what he originally suggested. Sometimes a person should just listen instead of trying to think.
Thanks Claudio for a great devise
Don
I have built Claudios gadget and have made a few experimental sails.I do not understand how you decide how much draft is allowed at each seam in a sail. Can someone give me some help with this?
For me that was pretty much a trial and error thing. If you see in my last post I am down to .35mm wedges. I am making US1M sails. The longest seam is about 10"(forgive the mixed measurements) and there are 4 seams in the main and 3 in the jib. This gives me about 8 to 10% draft althought I haven’t actually measured it. I find that the outhaul gives the bulk of the camber. The broadseaming just gives enough shape to stop the sail from flopping around. When you lay my last set on a flat surface you can just barely see that there is a little pucker(for lack of a better word) around the seams.
Hope this helps, if not try re-phrasing your question. Sometimes I have trouble understanding what people are asking.
Don
Yes it is difficult to put this into words, I wish you could see me waving my arms about. Using Claudios gadget I can put whatever camber I want at each seam. For example do I put 2% at the bottom seam 8% in the next seam 6% at the next one up and then 4% in the top seam ???. Or is there some other combination of induced camber that should be typically better. Seems to me there must be a piece of theory somewhere that deals with this (without needing a degree in advanced mathematics).
My rule of thumb based only on experience - not on sailmaking - and it may not relate from the real world to the small world, and from cat to monohull - but our cat sails were always cut to the “flat” side due to apparent wind speed - with the top of the sail being very flat and the boat being very light weight generating lots of apparent wind!
On a monohull, due to it’s relative weight (keel bulb) sails are usually cut “fuller” but if full at the top, there would be a lot of power too high up causing the boat to heel in medium or high winds. I would think the idea is to flatten the sails near the top on a monohull as well.
As to how much camber and it’s specific location - now we need to start discussing the class type. On our cats we are full camber at about 30-40% back from mast. With wind gusts, the maximum camber might move aft beyond 50% - and closer to 65-70%
Probably need to pick up a good book on sail design if you really want to understand the science. I stay at the fringes of the technology - others are really deep into it.
The last few sails I have been useing the same thickness wedge in all the seams. This adds a little camber as you go up the sail. This puts a (very) little cup in the top seam which the US1M sails need because the large roach tries to flop over. And because the outhaul mainly affects the bottom half or two-thirds you don’t need that much camber in the bottom seams. I have made a set where the first seam is halfway up the sail and it seemd to set nicely.
Don
Thank you Dick and Don, I am sure there are a few (those who make sails and sell them) who could add some good advice on this subject. Maybe it is as confidential as to where sail cloth can be found.
Not to worry seems some experimenting needs to be done.
For sailmaking supplies you can try: <<www.midwestmodelyachting.com>> They sell wee little eyelets & ¼” wide super seamstick tape, among other things. For actual sailcloth take a look at: <<www.sailrite.com>> They will sell cloth in one yard increments. Kite shops are also another source for fabric. For the sweetest in standing rigging components take a gander at: <<www.modelyachtfittings.com>>
Happy Yachting - Kip
Well, this thread has been running for almost two years and there hasn’t been a response from a pro sailmaker so I wouldn’t hold your breath. As I think about it I don’t think there has been much or any comment on sail design. The whole thread has been a “how to make” not “how to design”. The only solid thing I have discovered is to go light on the camber. I have always (6 years) made my own sails and most of them “looked good” but I was fighting a weather helm problem the whole time. Finally someone (Hiljoball)suggested that I might have too much camber. I started making them flatter and my weather helm problem went away(or at least became managable). Find yourself a drafting shop where you can get 2 mil mylar cheap. Tyvek house wrap makes a good test material. Don’t worry about appearance(color, printing on the mylar etc). Make lots of sails. Find a buddy to sail with. Sailing by yourself proves nothing. If a boat is more than 10(somedays 5) feet away it is not a good comparison. Keep records. Have one page for each set and write down everthing you do for that set. Number each set with permanent ink(personal experience). Don’t pay any attention to people that are laughing at your sails, you are doing an art form that most are afraid to try. When you do build a set that leaves them in the mist then use good sail material. When people start paying you to make sails for them charge those that laughed double. Oh, and don’t give away all your secrets;)
except maybe to me
Good luck
Don
Oh, any or all of this could be dead wrong, I’ve only started.
Making Model Yacht Sails
by
Larry Robinson is a good book , it not only tells how to make blocks for sailmaking( if you want to go that route) but has info on camber distribution and alot of other good stuff. It is worth the money.
http://www.midwestmodelyachting.com/products/sail_making/csailmake07.html
I also printed out that whole thread on sailmaking. Really go through it and you will find some good information.
Has anyone tried making sails from DuPont " Tyvek" building wrap material ? From all accounts it would seem to be suitable, just wondering if anyone has any experience of it.
cheers
John
John -
I tried some “Kite Studio” Tyvek material for my 1 meter multihull. It is supposed to be of “softer hand” (not so stiff) as the house wrap material, but if I were pushed for a comment, I guess I would say … “Ummmm - it was OK.”
Not exciting, panels taped up easily, could decorate as it had no over-printing, but the Tri-Spi and lighter Mylars seem to “set” better when mounted on a rig. I would not use for racing sails, but if you are looking for something to make sail designs without a lot of cost, you could consider this stuff. Unfortunately, the 1.5 oz. Nylon ripstop ( especially seconds) is less expensive, plus you have the choice of a lot of colors.
The “real” housewrap is pretty stiff and perhaps good only for small storm sails. (in my opinion)
I made a set from the house wrap and except for the partial letters and the noise they were OK. Oh, they winkled quite easily and did I mention they were noisey. If they got dirty they weren’t easy to clean and they were noisey.
Don
Using the Claudio tool…
Will it work for most any size sails? It seems like most people are using this tool for making sails to fit a 1M or Marblehead/12M.
What about the Footy sails? Is there anything to adjust or change when working with something that small?
thx
I was able to soften a couple square yards of the stiff Tyvek by putting it under my asian rug for a few weeks. You might even put it under your bedsheets or between matress & boxspring.
Hi Dick and all.
here some pictures of the IOms build by the kids at the puclic school were I do the R/C sailing course all year long from march to december.
The sails are in Tyverk, the house warping material, veruy stiff, so there are no battens on the sails!! once tuuned up, they sail very well, even the Nº9 won a race against a TS-2 . Of couse the TS-2 skeeper was not paying to much attention to the race, but since that moments the kids earned the respectec of the rest of skeepers and started to look them more seriously.
But i agree the tyvek is not near the best material for good performance. I have used ripstop .65 to .75 oz and seems to be nice for A and B rigs. carbon battens.
Tato Lazo
Did anyone archive the images and writeup for the use of the Claudio tool? All the images have disappeared, especially the charts for the wedges, etc. Also, the minicoque website seems to be gone ( so is Wis- coincidence?). 
but since I can’t read French…
thx
Hi all, well I just made my 1st sail using the Claudio tool, it worked great, the sail didn’t turn out to good but it was my first and I was using 1mil mylar. If anyone can help me on how to use the graph I would appreciate it. For Tomo I attached the file that he was looking for.
john
Hi:
I have built the two blocks used to build paneled sails for IOM. IT is just that i think that i need to know how to build them to understand how they work and then be able to trim better my sailboat.
Last night i made some practice with fotocopy paper, and the 21 cms high and 33 cms. wide panels were nicely glued together, but i noticed that the curve induced was not as much as expected.
Do you have any idea how much should I rise the panels at the center when put togheter each of the 4 panels in themail sail and the three o the jib??
I have tried with 1 and 4 mm but it seems to be insuficient. later i tried with 7,mm and the final result seems to be a more noticeable curve from front to back and a little curve from top to bottom in the “sail”
Hope you can help, in the meanwhile…i keep searching, reading, etc.
Tato Lazo
P.D. Pictures later.
Try this site. Ben has done a great job.
http://www.stirling.saradioyachting.org.au/sailmaking.htm
Don